/**
 * @file
 * SNMP table support implementation.
 */

/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Martin Hentschel <info@cl-soft.de>
 *
 */

#include "lwip/apps/snmp_opts.h"

#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */

#include "lwip/apps/snmp_core.h"
#include "lwip/apps/snmp_table.h"
#include <string.h>

snmp_err_t snmp_table_get_instance(const u32_t* root_oid, u8_t root_oid_len, struct snmp_node_instance* instance)
{
	snmp_err_t ret = SNMP_ERR_NOSUCHINSTANCE;
	const struct snmp_table_node* table_node = (const struct snmp_table_node*)(const void*)instance->node;

	LWIP_UNUSED_ARG(root_oid);
	LWIP_UNUSED_ARG(root_oid_len);

	/* check min. length (fixed row entry definition, column, row instance oid with at least one entry */
	/* fixed row entry always has oid 1 */
	if((instance->instance_oid.len >= 3) && (instance->instance_oid.id[0] == 1)) {
		/* search column */
		const struct snmp_table_col_def* col_def = table_node->columns;
		u16_t i = table_node->column_count;

		while(i > 0) {
			if(col_def->index == instance->instance_oid.id[1]) {
				break;
			}

			col_def++;
			i--;
		}

		if(i > 0) {
			/* everything may be overwritten by get_cell_instance_method() in order to implement special handling for single columns/cells */
			instance->asn1_type = col_def->asn1_type;
			instance->access    = col_def->access;
			instance->get_value = table_node->get_value;
			instance->set_test  = table_node->set_test;
			instance->set_value = table_node->set_value;

			ret = table_node->get_cell_instance(
			          &(instance->instance_oid.id[1]),
			          &(instance->instance_oid.id[2]),
			          instance->instance_oid.len - 2,
			          instance);
		}
	}

	return ret;
}

snmp_err_t snmp_table_get_next_instance(const u32_t* root_oid, u8_t root_oid_len, struct snmp_node_instance* instance)
{
	const struct snmp_table_node* table_node = (const struct snmp_table_node*)(const void*)instance->node;
	const struct snmp_table_col_def* col_def;
	struct snmp_obj_id row_oid;
	u32_t column = 0;
	snmp_err_t result;

	LWIP_UNUSED_ARG(root_oid);
	LWIP_UNUSED_ARG(root_oid_len);

	/* check that first part of id is 0 or 1, referencing fixed row entry */
	if((instance->instance_oid.len > 0) && (instance->instance_oid.id[0] > 1)) {
		return SNMP_ERR_NOSUCHINSTANCE;
	}

	if(instance->instance_oid.len > 1) {
		column = instance->instance_oid.id[1];
	}

	if(instance->instance_oid.len > 2) {
		snmp_oid_assign(&row_oid, &(instance->instance_oid.id[2]), instance->instance_oid.len - 2);
	} else {
		row_oid.len = 0;
	}

	instance->get_value    = table_node->get_value;
	instance->set_test     = table_node->set_test;
	instance->set_value    = table_node->set_value;

	/* resolve column and value */
	do {
		u16_t i;
		const struct snmp_table_col_def* next_col_def = NULL;
		col_def = table_node->columns;

		for(i = 0; i < table_node->column_count; i++) {
			if(col_def->index == column) {
				next_col_def = col_def;
				break;
			} else if((col_def->index > column) && ((next_col_def == NULL) || (col_def->index < next_col_def->index))) {
				next_col_def = col_def;
			}

			col_def++;
		}

		if(next_col_def == NULL) {
			/* no further column found */
			return SNMP_ERR_NOSUCHINSTANCE;
		}

		instance->asn1_type          = next_col_def->asn1_type;
		instance->access             = next_col_def->access;

		result = table_node->get_next_cell_instance(
		             &next_col_def->index,
		             &row_oid,
		             instance);

		if(result == SNMP_ERR_NOERROR) {
			col_def = next_col_def;
			break;
		}

		row_oid.len = 0; /* reset row_oid because we switch to next column and start with the first entry there */
		column = next_col_def->index + 1;
	} while(1);

	/* build resulting oid */
	instance->instance_oid.len   = 2;
	instance->instance_oid.id[0] = 1;
	instance->instance_oid.id[1] = col_def->index;
	snmp_oid_append(&instance->instance_oid, row_oid.id, row_oid.len);

	return SNMP_ERR_NOERROR;
}


snmp_err_t snmp_table_simple_get_instance(const u32_t* root_oid, u8_t root_oid_len, struct snmp_node_instance* instance)
{
	snmp_err_t ret = SNMP_ERR_NOSUCHINSTANCE;
	const struct snmp_table_simple_node* table_node = (const struct snmp_table_simple_node*)(const void*)instance->node;

	LWIP_UNUSED_ARG(root_oid);
	LWIP_UNUSED_ARG(root_oid_len);

	/* check min. length (fixed row entry definition, column, row instance oid with at least one entry */
	/* fixed row entry always has oid 1 */
	if((instance->instance_oid.len >= 3) && (instance->instance_oid.id[0] == 1)) {
		ret = table_node->get_cell_value(
		          &(instance->instance_oid.id[1]),
		          &(instance->instance_oid.id[2]),
		          instance->instance_oid.len - 2,
		          &instance->reference,
		          &instance->reference_len);

		if(ret == SNMP_ERR_NOERROR) {
			/* search column */
			const struct snmp_table_simple_col_def* col_def = table_node->columns;
			u32_t i = table_node->column_count;

			while(i > 0) {
				if(col_def->index == instance->instance_oid.id[1]) {
					break;
				}

				col_def++;
				i--;
			}

			if(i > 0) {
				instance->asn1_type = col_def->asn1_type;
				instance->access    = SNMP_NODE_INSTANCE_READ_ONLY;
				instance->set_test  = NULL;
				instance->set_value = NULL;

				switch(col_def->data_type) {
					case SNMP_VARIANT_VALUE_TYPE_U32:
						instance->get_value = snmp_table_extract_value_from_u32ref;
						break;

					case SNMP_VARIANT_VALUE_TYPE_S32:
						instance->get_value = snmp_table_extract_value_from_s32ref;
						break;

					case SNMP_VARIANT_VALUE_TYPE_PTR: /* fall through */
					case SNMP_VARIANT_VALUE_TYPE_CONST_PTR:
						instance->get_value = snmp_table_extract_value_from_refconstptr;
						break;

					default:
						LWIP_DEBUGF(SNMP_DEBUG, ("snmp_table_simple_get_instance(): unknown column data_type: %d\n", col_def->data_type));
						return SNMP_ERR_GENERROR;
				}

				ret = SNMP_ERR_NOERROR;
			} else {
				ret = SNMP_ERR_NOSUCHINSTANCE;
			}
		}
	}

	return ret;
}

snmp_err_t snmp_table_simple_get_next_instance(const u32_t* root_oid, u8_t root_oid_len, struct snmp_node_instance* instance)
{
	const struct snmp_table_simple_node* table_node = (const struct snmp_table_simple_node*)(const void*)instance->node;
	const struct snmp_table_simple_col_def* col_def;
	struct snmp_obj_id row_oid;
	u32_t column = 0;
	snmp_err_t result;

	LWIP_UNUSED_ARG(root_oid);
	LWIP_UNUSED_ARG(root_oid_len);

	/* check that first part of id is 0 or 1, referencing fixed row entry */
	if((instance->instance_oid.len > 0) && (instance->instance_oid.id[0] > 1)) {
		return SNMP_ERR_NOSUCHINSTANCE;
	}

	if(instance->instance_oid.len > 1) {
		column = instance->instance_oid.id[1];
	}

	if(instance->instance_oid.len > 2) {
		snmp_oid_assign(&row_oid, &(instance->instance_oid.id[2]), instance->instance_oid.len - 2);
	} else {
		row_oid.len = 0;
	}

	/* resolve column and value */
	do {
		u32_t i;
		const struct snmp_table_simple_col_def* next_col_def = NULL;
		col_def = table_node->columns;

		for(i = 0; i < table_node->column_count; i++) {
			if(col_def->index == column) {
				next_col_def = col_def;
				break;
			} else if((col_def->index > column) && ((next_col_def == NULL) ||
			                                        (col_def->index < next_col_def->index))) {
				next_col_def = col_def;
			}

			col_def++;
		}

		if(next_col_def == NULL) {
			/* no further column found */
			return SNMP_ERR_NOSUCHINSTANCE;
		}

		result = table_node->get_next_cell_instance_and_value(
		             &next_col_def->index,
		             &row_oid,
		             &instance->reference,
		             &instance->reference_len);

		if(result == SNMP_ERR_NOERROR) {
			col_def = next_col_def;
			break;
		}

		row_oid.len = 0; /* reset row_oid because we switch to next column and start with the first entry there */
		column = next_col_def->index + 1;
	} while(1);

	instance->asn1_type = col_def->asn1_type;
	instance->access    = SNMP_NODE_INSTANCE_READ_ONLY;
	instance->set_test  = NULL;
	instance->set_value = NULL;

	switch(col_def->data_type) {
		case SNMP_VARIANT_VALUE_TYPE_U32:
			instance->get_value = snmp_table_extract_value_from_u32ref;
			break;

		case SNMP_VARIANT_VALUE_TYPE_S32:
			instance->get_value = snmp_table_extract_value_from_s32ref;
			break;

		case SNMP_VARIANT_VALUE_TYPE_PTR: /* fall through */
		case SNMP_VARIANT_VALUE_TYPE_CONST_PTR:
			instance->get_value = snmp_table_extract_value_from_refconstptr;
			break;

		default:
			LWIP_DEBUGF(SNMP_DEBUG, ("snmp_table_simple_get_instance(): unknown column data_type: %d\n", col_def->data_type));
			return SNMP_ERR_GENERROR;
	}

	/* build resulting oid */
	instance->instance_oid.len   = 2;
	instance->instance_oid.id[0] = 1;
	instance->instance_oid.id[1] = col_def->index;
	snmp_oid_append(&instance->instance_oid, row_oid.id, row_oid.len);

	return SNMP_ERR_NOERROR;
}


s16_t
snmp_table_extract_value_from_s32ref(struct snmp_node_instance* instance, void* value)
{
	s32_t* dst = (s32_t*)value;
	*dst = instance->reference.s32;
	return sizeof(*dst);
}

s16_t
snmp_table_extract_value_from_u32ref(struct snmp_node_instance* instance, void* value)
{
	u32_t* dst = (u32_t*)value;
	*dst = instance->reference.u32;
	return sizeof(*dst);
}

s16_t
snmp_table_extract_value_from_refconstptr(struct snmp_node_instance* instance, void* value)
{
	MEMCPY(value, instance->reference.const_ptr, instance->reference_len);
	return (u16_t)instance->reference_len;
}

#endif /* LWIP_SNMP */
